STRATIGRAPHIC ARCHITECTURE AND RESERVOIR CHARACTERIZATION OF THE SILURIAN RACINE FORMATION, FORSYTH
FIELD, CENTRAL ILLINOIS
Yaghoob Lasemi
Illinois State Geological Survey, University
of Illinois at Urbana-Champaign
Geological Society of America Annual Meeting, October 2017
Acknowledgements
This work is partially funded by the U.S. Department of
Energy – National Energy Technology Laboratory through
CarbonSAFE Illinois–Macon County Grant No. DE-
FE0029381 (Steven G. Whittaker PI). Original draft of
contour maps and cross-sections were prepared using IHS
PETRA through their University Grant Program.
1. Geologic setting
2. Field discovery and development
3. Stratigraphy and reservoir characterization
4. Reservoir development and petroleum entrapment
5. Potential for future development
Presentation Outline
Illin
ois
Ba
sin
Du
rin
g S
ilu
ria
n T
ime
(M
od
ifie
d
fro
m L
as
em
i e
t a
l., 2
01
0;
La
se
mi, 2
01
4)
Illin
ois
Ba
sin
an
d t
he
Su
rro
un
din
g A
rch
es
a
nd
Do
me
s (
Ko
lata
an
d N
els
on
, 2
01
0)
Mt.
Au
bu
rn T
ren
d O
il F
ield
s i
n t
he
So
uth
ern
Fla
nk o
f th
e S
an
gam
on
Arc
h
Reen
try i
n S
ch
warz
# 1
, an
Old
Dry
Ho
le,
Led
to
Dis
co
very
in
196
3
An
nu
al
Oil P
rod
uc
tio
n,
19
63
-201
3;
Majo
r D
eve
lop
men
t in
Ea
rly 8
0s
Stratigraphy and Correlation
Str
ati
gra
ph
ic N
om
en
cla
ture
of
the
Silu
ria
n S
ys
tem
an
d G
lob
al S
ea
Le
ve
l C
ha
ng
es
(R
ac
ine
Su
bd
ivis
ion
fr
om
La
se
mi, 2
00
9;
La
se
mi e
t a
l., 2
01
0)
Ge
ne
ral
Str
ati
gra
ph
ic C
olu
mn
,
So
uth
eas
t M
arg
in o
f th
e S
an
gam
on
Arc
h
Stratigraphic Reference Section (Schwarze-Pense Com. No. 2, API #121152144400)
Reservoir Occurrence
and Variability
So
uth
west-
No
rth
east
Str
ati
gra
ph
ic
Co
rrela
tio
n,
Mt.
Au
bu
rn T
ren
d
No
rth
west-
So
uth
east
Str
ati
gra
ph
ic
Co
rrela
tio
n,
Fo
rsyth
Fie
ld
So
uth
we
st-
No
rth
eas
t S
trati
gra
ph
ic
Co
rrela
tio
n,
Fo
rsyth
Fie
ld
So
uth
-to
-No
rth
Str
ati
gra
ph
ic C
orr
ela
tio
n,
Fo
rsyth
Fie
ld
Res
erv
oir
Co
mp
art
men
ts D
evelo
ped
in t
he
Hig
hsta
nd
Packag
e o
f th
e U
pp
er
Racin
e S
eq
uen
ce
Co
re S
am
ple
s f
rom
Po
do
lsky
Oil
Co
.
Mc
Mil
len
B-4
, M
t. A
ub
urn
Co
nso
lid
ate
d F
ield
, C
hri
sti
an
Co
un
ty
Depositional and Diagenetic Model for Reservoir Development
in the Silurian Deposits of the Study Area (Photomicrograph Scale Bar: 0.5 mm)
Thickness Map of the Main Reservoir Reservoir Top Structure Contour Map
Potential for Improving Recovery
1. Calculated OOIP: Over
10,000,000 barrels.
2. Production per well: Less
than 10,000 bbl./solution gas
and gravity drive.
3. DST: Low SIP and negligible
fluid recovery.
4. Initial oil production: Nearly
40 bbl. Average.
Poor Reservoir
Performance
1. Infill drilling.
2. Development of undrilled areas.
3. Larger volume hydraulic fracturing.
4. Horizontal drilling.
5. Enhanced recovery through
waterflooding or CO2 EOR.
Suggestions for
Increased Production
The Silurian reservoir interval at Forsyth consists of dolomite bodies
that occur in the upper part of small scale cycles, which suggest sea
level fluctuation as the major control for their development.
Low recorded shut-in pressure and negligible fluid recovery in DST,
insignificant initial oil production, and below average cumulative primary
production per well suggest poor permeability.
Infill drilling and development of the undrilled areas, large volume
hydraulic fracturing, and horizontal drilling could lead to significant
increased production from the field.
The field has produced less than 10% of its OOIP and has never been
flooded. It has a great potential for significant increased recovery
through waterflooding and CO2-EOR.
Conclusions
Thank You